Self-propelling ballistic projectiles

ABSTRACT

Ballistic projectiles for firearms and more particularly to a self-propelling ballistic projectile which, upon firing, is totally expelled from the firearm without leaving a residual case therein.

United States Patent 1191 Iniantino June 11, 1974 [54] SELF-PROPELLINGBALLlSTlC [56] References Cited PROJECTILES UNITED STATES PATENTS [75]Inventor: Osvaldo Cesar Iniantino, Buenos 750,623 1/1904 Edmundsm102/497 Aires, Argentina 1,191,357 7/1916 Snyder lO2/49.7 1,446,7112/1923 Ludorf 102/497 Asslgneei Dll'mwn General de lljvfrstlgaclon y1,468,822 9/1923 Ludorf 102/497 Desarrollo (DIGID) Ministry of 1,481,8721/1924 Miller 102/497 Defense of the Argentine Republic, 2,424,9347/1947 Kasper 102/497 Buenos Aires, Argentina 3,398,684 8/1968 Kuavle102/497 X [22] Filed: 1971 Primary Examiner-Samuel Feinberg [21] Appl.No.: 189,905 Assistant Examiner-H. J. Tudor Attorney, Agent, orFirmLerner, David, Littenberg 30 Foreign Application Priority DataSamuel Oct. 19, 1970 Argentina 231877 57 ABSTRACT Ballistic projectilesfor firearms and more particularly 'ga g g to a self-propellingballistic projectile which, upon 11:. l 58] Fieid 7 DIG 1 ing, istotally expelled from the firearm without leaving a residual casetherein.

4 Claims, 6 Drawing Figures SELF-PROPELLING BALLISTIC PROJECTILESConventional fireami cartridges comprise a case, a projectile or bulletfitted at the mouth end of the case, a propellant charge inside thecase, and priming means at the rear end of the case. These cartridgesare loaded into the chamber of a firearm and, upon being fired, thepropellant charge impells the projectile or bullet through the barrel ofthe firearm. The case is retained in the chamber and elaborate meanshave been devised to eject it either manually or automatically.

Theseejecting means are prone to malfunction and are a major cause ofjamming. Besides, the necessity of ejecting the residual case reducesthe frequency of firing and severely limits the efiectiveness of thefirearm.

In addition, conventional cartridges comprise several independent partsrequiring an elaborated manufacturing process which makes them ratherexpensive.

It is also evident that the bullet proper is only a fraction of thetotal weight of the cartridge and therefore, storage volume andtransportation costs are disproportioned to the effectiveness of theammunition.

Efforts to improve firearm ammunition in the recent past were directedtowards reducing barrel erosion and attaining improved ballisticperformance.

Modern firearms have barrel bores with a series of equidistant parallelgroves (called rifling) which spiral from one end of the barrel to theother. These groves or rifling define land portions which bite into thesurface of the bullet while it travels through the bore and causes it tospin. The gyroscopic effect thus created helps to stabilize the path ofthe bullet and increases the accuracy of fire.

The outer diameter of the bullet is, of necessity, slightly larger thanthe inner diameter across the lands of the bore and, as a consequence,the bore is subjected to sever erosion.

In view of the above-mentioned problems, several attempts have been madeto produce a self-propelling ballistic projectile which is totallyexpelled through the barrel of the firearm from which it is fired. Theseattempts have not been successful mainly because the self-propellingprojectiles were designed on the same criteria used for conventionalammunition, namely, the body of the projectiles had a diameter largerthan the inner diameter across the lands of the barrel bore so that thelands of the bore bit into the surface of the projectile and imparted toit the above-referred to spinning motion.

This oversizing of the projectile body and the expansion it experiencedunder the pressure of firing, subjected the bore to severe erosion,decreased appreciably the kinetic energy of the projectile, and causedexcessive gas leakage through the firearm chamber.

Other attempts to solve the above problem were centered about the designof a self-destroying case, but this created other problems whichrendered this solution totally ineffective.

With a view to solving the problems normally associated withconventional ammunition andknown selfpropelling projectiles, the presentinvention provides a ballistic, self-propelling projectile adapted to befired from a firearm having a helically grooved bore and capable ofbeing totally expelled through said bore without leaving any residue inthe firearm, said projectile comprising a body of substantiallycylindro-ogival shape, having a propellant cavity therein, priming meansin said propellant cavity, and an outer, peripheral flange at therear,"terminal end of said body and integral therewith; the maximumouter diameter of said body being equal to, or slightly less than thediameter of said bore across the lands defined between said grooves; andthe outer diameter of said rear peripheral flange being larger than thediameter of the bore across said lands; whereby, upon the projectilebeing fired and impelled through the bore, said rear peripheral flangeis bit and deformed by the lands in the bore, and the projectile bodyexpands under the pressure of firing and engages the lands in the borethus causing the projectile to spin while it travels through the bore.

The basic principle of the invention resides in making the maximum outerdiameter of the projectile body, equal or slightly less than thediameter of the bore of the firearm from which the projectile is to befired. The desired spinning motion is produced, on the one hand, by arear peripheral flange which, upon firing of the projectile, engages andis deformed by the rifling in the bore, and on the other hand, byengagement of the surface of the projectile with the rifling in the boreclue to the expansion caused by the ignition of the propellant charge.

This principle may be applied to ammunition of a wide range of calibresand intended for diverse types of firearms, such as portable, automatic,semi-automatic, or artillery weapons.

The main advantages of the invention are the elimination of the residualcase and the reduction of barrel erosion. Other advantages are:

l. Supersonic munle velocity with the consequent increase in impactenergy.

2. Higher offensive power since the full projectile structure strikesthe target.

3. Less firearm recoil.

4. Lower manufacturing costs.

5. Possibility of simplifying the firearms using amm unition inaccordance with the invention by eliminating the case ejecting mechanismand this eliminates a major source of mechanical trouble.

6. Possibility of increasing the frequency of firing by decreasing thefiring cycle.

7. Lower weight, storage volume and transportation costs.

8. Better resistance to water and humidity.

The invention will now be described with reference to the accompanyingdrawings which illustrate, by way of example, a preferred embodiment ofthe invention.

In the drawings:

FIG. 1 is an elevation view, partially in section, of a ballisticprojectile according to the invention.

FIG. 2 shows schematically the projectile of the invention in thechamber of a firearm, prior to firing.

FIG. 3 is a cross section along line III-III of FIG. 2.

FIG. 4 is a view similar to that of FIG. 2 but immediately after theprojectile has been fired.

FIG. 5 is a cross section along line V-V of FIG. 4.

FIG. 6 is a perspective view of the projectile immediately after beingfired showing the deformation of the rear peripheral flange.

With reference now to the drawings, the selfpropelling ballisticprojectile shown in FIG. 1 comprises a single-piece body 1, preferablyof cylindroogival shape, having an internal ogival or cylindroogivalpropellant cavity 2. The propellant cavity is closed at the rear end ofthe body by priming means 3 which could be of the central fire or ringfire type.

4 It should be noted that the rear flange 6 acts as a stop for theprojectile in the chamber before the projectile is fired, and also as aguiding ring while the projectile travels through the bore. ltfurthermore assists in stabi- The priming means 3 rest on an internalshoulder 4 5 lizing the projectile after it is expelled from the barrel.provided in the wall of the projectile body. I FIG. 5 is a cross sectionthrough line V-V of FIG. The propellant cavity contains a propellantcharge 5 4 showing schematically the deformation or extrusion which mayconsist of common gun powder. suffered by the projectile whiletraversing the bore. The The projectile body 1 has, at its rear terminalend, an reference numeral 12 indicates the clearance between outerperipheral flange 6 formed integrally with the the bore and theprojectile. projectile body and extending substantially at right an- Theremnants of the primer 3 are expelled. together gles with respect to thelongitudinal axis of the projecwith the projectile through the barrel.To accomplish tile. The outer diameter of the flange 6 is larger thanthis, several primer designs are possible and it is not the outerdiameter of the cylindrical portion of the proconsidered necessary todiscuss them in detail. It will be jectile body. The diameter andthickness of the flange l5 apparent to those expert in the art, that thepriming 6 depend on the calibre of the projectile. means may be locatedat either end of the propellant In FIG. 2 the projectile is shown in thechamber C of cavity. a firearm prior to firing. The firearm barrel 7 hasa se- The projectile body is preferably made of a brass ries of parallelgrooves 8 which spiral from the chamber alloy although other suitablemetals could also be emend to the muzzle end of the barrel and defineland porplayed. I tions 9 therebetween. The performance of theself-propelling projectile of In the position shown in FIG. 2 the rearflange of the the invention was compared with conventionalammuprojectile abutts against shoulder means 10 provided in n n Qt: thesame and different calibre. n h the chamber which hold it in place. Asit may be best The -P P prolectlle tested had the followseen in FIG. 3,the outer diameter of the projectile g Characteflstlcsi body is equalor, preferably, slightly less than the inner diameter, across the lands,of the bore. Calibre 9 mm As an example, a desirable clearance between acalied) 5 1; bre 9 pro ectile and the bore of the correspondmg fire-Propellant charge 330 mg arm is in the order of 0.006 mm.

FIG. 4 shows the projectile immediately after it has The results of thetests are indicated in the attached tabeen fired by percussion of thepriming means 3 with ble. the percussion pin (not shown) of the firearm.As it can The tests showed that the muzzle velocity of the probest beseen in FIG. 6, the rear flange 6 of the projectile jectile of theinvention was frankly supersonic and subis deformed by the rifling andscrews into the helical stantially higher than that of all theammunition comgrooves of the bore. This produces the spinning of thepared. The recoil energy of the projectile of the invenprojectile.Almost simultaneously, the projectile body tion was also substantiallyless than that of ammunition expands slightly under the pressure offiring and enof the same calibre. gages the lands in the bore, whichmaintain and guide Ballistic tests conducted in a subsonic tunnel showedthe spinning motion of the projectile until it abandons that theprojectile of the invention had excellent ballisthe barrel through themuzzle. In FIG. 6 it has been intic stability, i.e., its centre ofgravity followed a fixed dicated the indentations 11 formed by therifling on the path after the projectile left the barrel and thepropelsurface of the projectile body. lant charge became inert.

TABLE Test No. 279 280 281 282 283 on c.32 (3.32 c.9 C.9 Ammunition typelong long long PAM according and Calibre to DGFM DGFM ORBEA (TM) DGFMint/99M Initial Velocity jmlsec.) 348 270 31 1 327 455 Initial Energy(Kgm) 15 23 31 44 59 Recoil Energy K .m 0.260 0.308 0.500 0.430Dynamometer travel in) 0.241 0.284 0.460 0.372

Projectile Weight Ling) 2600 6300 6300 8100 6010 Common PropellantCharge Standard Standard Standard Standard hunting gun powder FANAZUL (TWinchester Specially Same PAM Same made Remarks barrel barrel as barrel9- as 0.53 m 0.18 in before standard before DGFMi Direccion General deFahricuciones Militares The stability conditions of the projectile ofthe invention were verified also with the Kranz equations.

An additional feature of the invention resides in the design of thepropellant cavity 2. The ogival or cylindro-ogival shape of the cavitypermits a better utiliza tion of of the explosive energy developed inthe projectile, and the use of a smaller propellant charge than would berequired in conventional ammunition equivalent calibre.

While the invention has been described in connection with a specificembodiment thereof, it is to be understood that this is by way ofillustration and not by way of limitation, and the scope of the appendedclaims should be construed as broadly as the prior art will permit.

What is claimed is:

l. A ballistic, self-propelling projectile adapted to be fired from afirearm having a helically grooved bore and capable of being totallyexpelled through said bore without leaving any residue in the firearm,said projectile comprising an expandable body of substantiallycylindro-ogival shape, the maximum outer diameter of said body beingequal to or slightly less than the diameter of said bore across thelands defined between said grooves, which body expands under pressure offiring and engages the lands of said bore, said body havinga propellantcavity therein, said propellant cavity being substantially ogival;priming means in said propellant cavity; and an outer, peripheral flangeat the rear, terminal end of said body and integral therewith, the outerdiameter of said rear peripheral flange being larger than the diameterof the bore across said lands, and serving as a stop for the projectilein the firearm chamber before firing, whereby, upon the projectile beingfired and impelled through the bore, said rear peripheral flange is bitand deformed by the lands in the bore which in conjunction withexpansion and engagement of the projectile body with the lands in thebore causes the projectile to spin while it travels through the bore.""ETTii ballistic, self-propelling projectile in accordance with claim 1wherein said outer peripheral flange has a rectangular cross section.

3. The ballistic self-propelling projectile in accordance with claim 1wherein said expandable body is made of a brass alloy.

4. The ballistic, self-propelling projectile in accordance with claim 1wherein said propellant cavity is of

1. A ballistic, self-propelling projectile adapted to be fired from afirearm having a helically grooved bore and capable of being totallyexpelled through said bore without leaving any residue in the firearm,said projectile comprising an expandable body of substantiallycylindro-ogival shape, the maximum outer diameter of said body beingequal to or slightly less than the diameter of said bore across thelands defined between said grooves, which body expands under pressure offiring and engages the lands of said bore, said body having a propellantcavity therein, said propellant cavity being substantially ogival;priming means in said propellant cavity; and an outer, peripheral flangeat the rear, terminal end of said body and integral therewith, the outerdiameter of said rear peripheral flange being larger than the diameterof the bore across said lands, and serving as a stop for the projectilein the firearm chamber before firing, whereby, upon the projectile beingfired and impelled through the bore, said rear peripheral flange is bitand deformed by the lands in the bore which in conjunction withexpansion and engagement of the projectile body with the lands in thebore causes the projectile to spin while it travels through the bore. 2.The ballistic, self-propelling projectile in accordance with claim 1wherein said outer peripheral flange has a rectangular cross section. 3.The ballistic self-propelling projectile in accordance with claim 1wherein said expandable body is made of a brass alloy.
 4. The ballistic,self-propelling projectile in accordance with claim 1 wherein saidpropellant cavity is of cylindro-ogival shape.